A typical cable network comprises a head end, which communicates with a cable modem termination system (CMTS) containing multiple transmitters and receivers. Each transmitter and receiver generally communicates with multiple cable modems (CMs) via a coaxial cable or hybrid fiber-coaxial network. The bandwidth between a CM and the CMTS is divided into a set of channels. For each node in the network, a receiver at the CMTS is generally allocated to each upstream channel that is in use, and a transmitter is allocated to each downstream channel.
Channel bonding in cable modems entered mainstream use with the introduction of the DOCSIS 3.0 specification. One or more bonded channels may be allocated to one or more of the CMs in communication with a CMTS. At times, the bonded channel(s) may become unsuitable for communication. To operate under these conditions, CMs may enter a partial service mode and discontinue use of the problematic channel, while continuing to operate using the remaining channels. The CM may continue ranging on the problematic channel, however, waiting for the partial service condition to be resolved such that it may again pass data on the channel.
A load balancing manager, detecting that there is little or no traffic on the channel impacted by a partial service condition, may consider the channel to be underutilized and actually assign additional modems to that channel. CMs newly moved by the load balancer to a bonding group that includes the channel impacted by the partial service condition may then also enter partial service mode because of the problem. Thus, the throughput of the CMs would be reduced, not increased, by the balancing operation. As the newly added modems also cease to pass traffic, the load balancer may be led to add more modems still to the impacted channel. Furthermore, modems entering partial service mode may shift more traffic to their other channels, potentially overloading those channels and starving modems for which only a single channel is available. When the CMs come out of partial service mode, the formerly impacted channel may quickly become overloaded, requiring further channel reallocations.
Thus, channel allocations using current load balancing techniques may not only be inefficient, but may also increase the chances of disruption of data and voice traffic.